Judge Jed Rakoff, talking with Judge Posner and Slate’s Joel Cohen, describes the Fifth Amendment right to remain silent as one example of the tension between truth and justice in American criminal law:
[O]ur Constitution allows a defendant to remain silent, even though that may in some sense impede the search for the truth.
The historic reason for this restriction is that in its absence, the government is easily persuaded to use torture to extract confessions—which is what happened in the English Star Chamber that gave rise to the Fifth Amendment privilege against self-incrimination. But is also commonplace today in legal systems like China’s, that don’t have such a privilege, and, at least for a time, was utilized in places like America’s Guantanamo Bay prison that were supposedly outside the reach of the Constitution.
While the Fifth Amendment is actually designed in part to advance the truth by guarding against coerced false confessions, it also serves the independent purpose of putting a check on government practices that most people consider repugnant regardless of their results. In short, while a legal system built on untruths is inherently unjust, truth is not the only requirement for achieving justice.